So, our population may not be representative of ICU patients in other countries. Nevertheless, the baseline characteristics, AKI incidence and proportion of patients receiving RRT were similar to those reported in previous studies [11,13].Finally, we did not have any information as to Ponatinib FDA the exact etiology of AKI, although sepsis was probably the commonest one. Of note, a recent study revealed that RIFLE classification can be used to evaluate the overall prognosis of septic patients, suggesting a close link between AKI and sepsis [40]. However, AKI often results from a combination of several risk factors whose respective contributions are difficult to determine. Whether any of these risk factors plays a preponderant role (or whether patients’ prognosis differs according to the cause of AKI) remains unknown.

ConclusionsWhile the prognosis for patients with AKI has long remained unclear because of the lack of a uniform definition, the recently published RIFLE criteria have facilitated epidemiological research in the field. Three multiple-center studies using conventional statistical models found an association between RIFLE class and mortality [10,11,13]. Original competing risks models reflecting “real life” more accurately are now available but are rarely used in the ICU setting. By applying such a model, this study confirms that AKI affecting critically ill patients is associated with increased mortality. However, further investigations focusing on the potential confusing role of RRT are warranted to better characterize the prognosis of AKI patients.

Key messages? The association of AKI with critically ill patients’ outcomes has been widely investigated, but very few multiple-center evaluations using recent consensus definition criteria have been published so far. Our study, carried out on a large cohort of general ICU patients, supports the use of RIFLE as a classification tool and adds to the current limited evidence that AKI negatively influences patients’ outcomes.? By applying an original competing risks approach and considering AKI as a time-dependent variable, we likely provided a refined estimation of the association between AKI and mortality as compared to previous reports.? Further investigations focusing on the potential confusing role of RRT are warranted to better characterize the prognosis of AKI.

AbbreviationsAKI: acute kidney injury; APACHE: Acute Physiology and Chronic Health Evaluation; ARF: acute renal failure; CIF: cumulative incidence function; GFR: glomerular filtration rate; ICU: intensive care unit; RIFLE: class R: Risk of renal dysfunction, class I: Injury to the kidney, class F: Failure of kidney GSK-3 function; class L: Loss of kidney function; and class E: End-stage kidney disease; RRT: renal replacement therapy; SAPS: Simplified Acute Physiology Score; SHR: subhazard ratio; SOFA: Sequential Organ Failure Assessment.